Process of making strawboard.



PETER PRINS, OF MINNEAPOLIS, MINNESOTA PROCESS OF MAKING: STRAWBOARDSpecification of Letters Patent.

. Ia'tented May 1,1906.

Application filed October 20. 1905. Serial 'No. 283 699 1'0 Mi whom itmay concern:

Be it known that I, PETER PnrNs, a subject of Queen Wilhelmena of theNetherlands, residing at Minneapolis, in the county of I-Iennepin andState of Minnesota, have invented certain new and useful Improvements inthe Processes oiMalkin Straw board; and I do hereby declare the ollowingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it appertains to make anduse the same.

My invention relates to a new and improved process for making hea paperor board from straw; and to this en it consists of the mode of treatmenthereinafter set forth in the specification and particularlypointed outin the claims.

I obtain the best results by carrying out the process in the followingmanner, to wit:

First. The straw is cut into short sections of about three inches inlength.

Second. This cut straw is placed in a closed retort and is thereincommingledwith quicklime in the proportion of .06 pounds of quicklinieto each pound of straw, The retort is rotated for about three and a halfhours and all the time steam is introduced into said retort under apressure of about five atmospheres per square inch, so that theconlmingled straw and quicklime is kept moist and hot. This second stepof the process reduces the straw to a fibrous condition and reduces thecomrningled mixture to a semifiuid condition.

Third. The fibrous pulp is ground up and reduced to a homogeneous mass.This may be done by any suitable grinder.

Fourth. The pulp is further reduced by a beating process or in intenseagitation, which alsg renders the pulp a lighter or less dense Fiith.The pulp is filtered and partially dried, and

Sixth. The dried or partially rolled, pressed, or ot erwise forme dried(pulp is into of steam while i the sheets of desired thickness to formthe strawboard or heavy straw pa er.

In practice I have found 1; rat the above process will effect a greatsaving in material and in the cost of the production of the completedboard. Furthermore, I have been ableto produce a better grade ofstrawbonrd by the above process.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is as follows: 1. A process for makin strawboard which consists,first, in cutting t e straw into short sections; second, in comrninglingthe straw with quicklime within a closed compartment, and insubjectingthe two to the action under agitation; third, in grinding up the fibrouspulp, to reduce the same to a homogeneous mass; fourth, in beating theround pulp, to further reduce and lighten t e same; fifth, in filtering,and atllast partially drying, the pulp; and sixth, in forming the pulpinto a sheet or sheets of desired thickness.

2. A process for makin strawboard which consists, first, in cutting thestraw into'short sections; second, in confining the straw in a closedretort, and commingling the same with quicklimo in the proportion of .06pounds of quicklime to onepound of straw, in introducin steam into saldretort under a pressure 0 about five atmospheres, and in keeping up an a'tation of the said straw and quicklime for a out three and a halfhours; third, in grinding up the fibrous pulp into a homogeneous mass;fourth, in beating the ground pulp, to further reduce the same; fifth,in filtering and'partiall .drying the pulp; and sixth, in pressing, rol'ng, or otherwise forrning the pulp into a sheet or sheets of desiredthickness.

In testimony whereof I affix my signature in presence of two witnesses.

. PETER PRINS. Witnesses:

A. LJJoNns, E. N. BAKER.

